Thanks to recent development in the electronic communication industry, portable electronic devices, such as mobile communication terminals (e.g., cellular phones), electronic organizers, Personal Digital Assistants (PDAs) have become necessities of modern life. Such electronic devices often use touch screens as a means for user input in combination with screen lock mechanisms that restrict access to those touchscreens. FIG. 1 depicts an example of one such screen lock mechanism. As shown, the screen lock provides a slide bar 11. When the slide bar 11 is moved to the right, the screen of the portable electronic device is unlocked. However, this mechanism is not completely secure because it allows the screen of the portable device to be unlocked by just about anyone.